Cars & Tinkerbell On Same Cake! Need Ideas Quick!!!

Hi all,I don't post often, but I need your help. I'm doing a joint birthday cake for friends of ours, and they would like a cars/tinkerbell cake! They also requested a sheet cake. I need some ideas as to how to incorporate those 2 themes, or should I decorate a sheet cake as 2 separate cakes? Please help. Any comments/ideas welcomed.Thanks in advance,Michelle

I would do 2 separate. From the kids stand point it stinks enough to have to share a birthday party, why not let them blow out their own cakes. Plus unless tink is riding a car, I'm not sure how to incorporate the two.